A fabric is, for instance, a switching network employed to interconnect servers and peripheral units. Fabric switch networks, such as those available with the Fiber Channel Storage Area Network technology, offered by International Business Machines Corporation, Armonk, N.Y., relieves the topology constraints imposed by a single switch environment. These networks enable the interconnection of geographically distant sites with a minimum number of fibre links. This is particularly beneficial to those customers that maintain data centers in two or more sites for disaster recovery.
Each end point (i.e., server or peripheral unit port) on the fabric is referred to as an N_Port and has, for instance, a 3-byte identifier. Each frame sent through the fabric carries the N_Port ID of the destination of that frame, and the fabric uses this ID to route the frame through the fabric.
In an open systems world, each server's operating system determines the N_Port IDs for the set of target peripheral units it can access through a discovery process, which includes sending queries to the name server facility within the fabric. It is then up to the operating system to determine which of the accessible targets it will actually use. This discovery approach is inherently insecure. That is, each operating system has visibility, and therefore, access to all of the peripheral units on the Storage Area Network, independent of whether it is allowed to use those units. Therefore, one operating system could corrupt, either by accident or intentionally, the data of another operating system. Further, this discovery approach does not provide a stable and predictable configuration. That is, the peripheral units that can be accessed by a server are not precisely defined.
Thus, a need exists for a capability that provides a secure environment. As one example, a need exists for a capability that predictably defines I/O configurations for environments that employ fabrics.